A deadly, complex disease

The mystery of Tara's demise has now been unravelled

We finally know what killed my little one-eyed cat Tara a few months ago. According to the necropsy (autopsy in humans), she died of feline infectious peritonitis (Fip).

The explanation I gave readers of Fip is, my vet friends tell me, not so accurate. My only excuse is that my source books are five years old, and in the last few years, researchers have made a lot of advances in understanding this mysterious disease.

Nevertheless, they still haven't found a cure for Fip.

We know that there are two kinds of presentation, the wet and the dry. In wet Fip, the cat's body retains fluids, usually in its belly. In this case, the disease strikes fast, without warning, and the cat dies within days, if not within hours.

In the dry type, the progress of the disease is much slower. I began to notice that Tara was sick when she was five or six months old. She fought her Fip for another six months.

In both cases, Fip seems to begin when the feline enteric coronavirus (Fecv) enters the cat's body. By itself, this virus doesn't cause Fip. Many cats acquire it, perhaps from their mothers or from other cats, and live long, healthy lives.

In some cats, however, the Fecv begins to multiply in large numbers, and some of these mutate into the Fip virus (FIPV).

Yet this new virus by itself doesn't cause Fip. Researchers suspect that the disease develops in some cats because their bodies over-react to Fipv. As the immune system fights the virus, it begins destroying the body itself.

In Tara's necropsy, researchers found evidence of Fipv. They also found lesions on all Tara's organs. Her own immune system caused them when it was fighting the virus.

The disease is much more complex and mysterious, however. Why would Tara die from Fip when other cats who carry both viruses live normal lives?

One possible explanation is that some kittens (just like humans) are much more sensitive to stress that other cats, and because of the stress, their immune systems become unable to handle the virus in their bodies.

Tara, growing up in a temple, fighting a terrible eye infection, would have faced enormous stress.

Another possible explanation is that there may be some kind of genetic weakness in the kittens whose immune systems are unable to handle the viruses in their bodies.

There is, as you can see, so much more about this disease than we now understand.

I know researchers are continuing to study this disease, and some have told me, as kindly as possible, that there was nothing I could have done to save the little cat.